/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package one.mixin.android.widget;

import android.content.Context;
import android.graphics.Matrix;
import android.util.AttributeSet;
import android.view.TextureView;
import android.view.View;
import android.widget.FrameLayout;
import androidx.annotation.IntDef;

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;

/**
 * A {@link FrameLayout} that resizes itself to match a specified aspect ratio.
 */
public class AspectRatioFrameLayout extends FrameLayout {

    /**
     * Listener to be notified about changes of the aspect ratios of this view.
     */
    public interface AspectRatioListener {

        /**
         * Called when either the target aspect ratio or the view aspect ratio is updated.
         *
         * @param targetAspectRatio   The aspect ratio that has been set in {@link #setAspectRatio(float)}
         * @param naturalAspectRatio  The natural aspect ratio of this view (before its width and height
         *                            are modified to satisfy the target aspect ratio).
         * @param aspectRatioMismatch Whether the target and natural aspect ratios differ enough for
         *                            changing the resize mode to have an effect.
         */
        void onAspectRatioUpdated(
                float targetAspectRatio, float naturalAspectRatio, boolean aspectRatioMismatch);
    }

    // LINT.IfChange

    /**
     * Resize modes for {@link AspectRatioFrameLayout}. One of {@link #RESIZE_MODE_FIT}, {@link
     * #RESIZE_MODE_FIXED_WIDTH}, {@link #RESIZE_MODE_FIXED_HEIGHT}, {@link #RESIZE_MODE_FILL} or
     * {@link #RESIZE_MODE_ZOOM}.
     */
    @Documented
    @Retention(RetentionPolicy.SOURCE)
    @IntDef({
            RESIZE_MODE_FIT,
            RESIZE_MODE_FIXED_WIDTH,
            RESIZE_MODE_FIXED_HEIGHT,
            RESIZE_MODE_FILL,
            RESIZE_MODE_ZOOM
    })
    public @interface ResizeMode {
    }

    /**
     * Either the width or height is decreased to obtain the desired aspect ratio.
     */
    public static final int RESIZE_MODE_FIT = 0;
    /**
     * The width is fixed and the height is increased or decreased to obtain the desired aspect ratio.
     */
    public static final int RESIZE_MODE_FIXED_WIDTH = 1;
    /**
     * The height is fixed and the width is increased or decreased to obtain the desired aspect ratio.
     */
    public static final int RESIZE_MODE_FIXED_HEIGHT = 2;
    /**
     * The specified aspect ratio is ignored.
     */
    public static final int RESIZE_MODE_FILL = 3;
    /**
     * Either the width or height is increased to obtain the desired aspect ratio.
     */
    public static final int RESIZE_MODE_ZOOM = 4;
    // LINT.ThenChange(../../../../../../res/values/attrs.xml)

    /**
     * The {@link FrameLayout} will not resize itself if the fractional difference between its natural
     * aspect ratio and the requested aspect ratio falls below this threshold.
     *
     * <p>This tolerance allows the view to occupy the whole of the screen when the requested aspect
     * ratio is very close, but not exactly equal to, the aspect ratio of the screen. This may reduce
     * the number of view layers that need to be composited by the underlying system, which can help
     * to reduce power consumption.
     */
    private static final float MAX_ASPECT_RATIO_DEFORMATION_FRACTION = 0.01f;

    private final AspectRatioUpdateDispatcher aspectRatioUpdateDispatcher;

    private AspectRatioListener aspectRatioListener;

    private float videoAspectRatio;
    private @ResizeMode
    int resizeMode;
    private boolean drawingReady;
    private int rotation;
    private Matrix matrix = new Matrix();

    public AspectRatioFrameLayout(Context context) {
        super(context);
        resizeMode = RESIZE_MODE_FIT;
        aspectRatioUpdateDispatcher = new AspectRatioUpdateDispatcher();
    }

    public AspectRatioFrameLayout(Context context, AttributeSet attributeSet) {
        super(context, attributeSet);
        resizeMode = RESIZE_MODE_FIT;
        aspectRatioUpdateDispatcher = new AspectRatioUpdateDispatcher();
    }

    public AspectRatioFrameLayout(Context context, AttributeSet attributeSet, int defStyleAttr) {
        super(context, attributeSet, defStyleAttr);
        resizeMode = RESIZE_MODE_FIT;
        aspectRatioUpdateDispatcher = new AspectRatioUpdateDispatcher();
    }

    /**
     * Sets the aspect ratio that this view should satisfy.
     *
     * @param widthHeightRatio The width to height ratio.
     */
    public void setAspectRatio(float widthHeightRatio, int rotation) {
        if (this.videoAspectRatio != widthHeightRatio) {
            this.videoAspectRatio = widthHeightRatio;
            this.rotation = rotation;
            requestLayout();
        }
    }

    /**
     * Sets the {@link AspectRatioListener}.
     *
     * @param listener The listener to be notified about aspect ratios changes.
     */
    public void setAspectRatioListener(AspectRatioListener listener) {
        this.aspectRatioListener = listener;
    }

    /**
     * Returns the {@link ResizeMode}.
     */
    public @ResizeMode
    int getResizeMode() {
        return resizeMode;
    }

    /**
     * Sets the {@link ResizeMode}
     *
     * @param resizeMode The {@link ResizeMode}.
     */
    public void setResizeMode(@ResizeMode int resizeMode) {
        if (this.resizeMode != resizeMode) {
            this.resizeMode = resizeMode;
            requestLayout();
        }
    }

    public void setDrawingReady(boolean value) {
        if (drawingReady == value) {
            return;
        }
        drawingReady = value;
    }

    public float getAspectRatio() {
        return videoAspectRatio;
    }

    public int getVideoRotation() {
        return rotation;
    }

    public boolean isDrawingReady() {
        return drawingReady;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (videoAspectRatio <= 0) {
            // Aspect ratio not set.
            return;
        }

        int width = getMeasuredWidth();
        int height = getMeasuredHeight();
        float viewAspectRatio = (float) width / height;
        float aspectDeformation = videoAspectRatio / viewAspectRatio - 1;
        if (Math.abs(aspectDeformation) <= MAX_ASPECT_RATIO_DEFORMATION_FRACTION) {
            // We're within the allowed tolerance.
            aspectRatioUpdateDispatcher.scheduleUpdate(videoAspectRatio, viewAspectRatio, false);
            return;
        }

        switch (resizeMode) {
            case RESIZE_MODE_FIXED_WIDTH:
                height = (int) (width / videoAspectRatio);
                break;
            case RESIZE_MODE_FIXED_HEIGHT:
                width = (int) (height * videoAspectRatio);
                break;
            case RESIZE_MODE_ZOOM:
                if (aspectDeformation > 0) {
                    width = (int) (height * videoAspectRatio);
                } else {
                    height = (int) (width / videoAspectRatio);
                }
                break;
            case RESIZE_MODE_FIT:
                if (aspectDeformation > 0) {
                    height = (int) (width / videoAspectRatio);
                } else {
                    width = (int) (height * videoAspectRatio);
                }
                break;
            case RESIZE_MODE_FILL:
                if (aspectDeformation <= 0) {
                    height = (int) (width / videoAspectRatio);
                } else {
                    width = (int) (height * videoAspectRatio);
                }
            default:
                // Ignore target aspect ratio
                break;
        }
        aspectRatioUpdateDispatcher.scheduleUpdate(videoAspectRatio, viewAspectRatio, true);
        super.onMeasure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY));

        int count = getChildCount();
        for (int a = 0; a < count; a++) {
            View child = getChildAt(a);
            if (child instanceof TextureView) {
                matrix.reset();
                int px = getWidth() / 2;
                int py = getHeight() / 2;
                matrix.postRotate(rotation, px, py);
                if (rotation == 90 || rotation == 270) {
                    float ratio = (float) getHeight() / getWidth();
                    matrix.postScale(1 / ratio, ratio, px, py);
                }
                ((TextureView) child).setTransform(matrix);
                break;
            }
        }
    }

    /**
     * Dispatches updates to {@link AspectRatioListener}.
     */
    private final class AspectRatioUpdateDispatcher implements Runnable {

        private float targetAspectRatio;
        private float naturalAspectRatio;
        private boolean aspectRatioMismatch;
        private boolean isScheduled;

        public void scheduleUpdate(
                float targetAspectRatio, float naturalAspectRatio, boolean aspectRatioMismatch) {
            this.targetAspectRatio = targetAspectRatio;
            this.naturalAspectRatio = naturalAspectRatio;
            this.aspectRatioMismatch = aspectRatioMismatch;

            if (!isScheduled) {
                isScheduled = true;
                post(this);
            }
        }

        @Override
        public void run() {
            isScheduled = false;
            if (aspectRatioListener == null) {
                return;
            }
            aspectRatioListener.onAspectRatioUpdated(
                    targetAspectRatio, naturalAspectRatio, aspectRatioMismatch);
        }
    }
}
